The present invention relates to improvements in mufflers or silencers for internal-combustion engines of the diesel variety, wherein the heat-of-compression causes the ignition of fuel-oil directly injected into the combustion chambers of said engines, and more particularly to a muffler comprising means to more effectively silence exhaust pulses; reduce back-pressure within the exhaust system; recover unburned fuel from the exhaust stream and; improve overall engine efficiency.
The depletion of the major portion of domestic petroleum reserves and the resultant increase in the cost of imported petroleum-based hydrocarbon fuels, such as those employed in internal-combustion engines of the diesel variety, has created the economic requirement to conserve energy and extract the maximum amount of energy from each gallon of fuel consumed. Further, the adverse effect upon the quality of the atmosphere, as well as the perceived deterioration of the Earth's protective ozone layer, has brought about an urgent environmental requirement to reduce the discharge of noxious airborne contaminants and particulate matter which are the products of combustion of such fuels. Additionally, the multiple explosions occurring within the cylinders of these internal-combustion engines must be silenced or muffled before they are released into the atmosphere lest they contribute to yet another environmental problem, noise pollution.
Attempts to find individual solutions to these problems often creates additional, and more complex problems for example, conventional exhaust silencers employ a multiplicity of small holes to accomplish their purpose. In a new condition these mufflers perform well. However, in use the small holes tend to become partially blocked by particles of carbon and rust, retarding the passage of the exhaust stream, increasing the back-pressure within the exhaust system and causing the engine to "breath" poorly. This results in poor fuel economy, degraded performance, increased emission of noxious fumes, gasses and particulate matter, and ultimately in the failure of exhaust valves and other engine parts.
A number of previous disclosures found in the prior art have addressed these problems. Among those disclosures, found in the patent literature of the United States, are the following: U.S. Pat. No. 3,498,406 by Heath; U.S. Pat. No. 3,733,827 by Zuzuki; U.S. Pat No. 3,799,133 by Frank; U.S. Pat. No. 3,842,808 by Cataldo; U.S. Pat. No. 4,087,966 by Akado and; U.S. Pat. No. 4,333,440 by Eheim. Unfortunately, the developments by these inventors do not appear to have seen wide commercialization or acceptance by the automotive industry, and as a consequence, neither the public nor the environment have derived a measurable benefit from their efforts.